Surface-protective apparatus



June 1l, 1940.

R. s. coLLEY 2,204,122 sUnrAcn-rnorzcnvs ummm y Fileduareh 9. 193e llllllllllllllllllllllll Il Patented June 11, 1940 PATENT OFFICE" SURFACE-PROTECTIVE APPARATUS Russell S. Colley, llient, Ohio, assigner to The B. F. Goodrich Company, New York, N. Y., a corporation of New York Application March 9, 1938, Serial No. 194,843

8 Claims.

This invention relates to surface-protective apparatus and is especially useful for preventing accumulation ofice upon surfaces such as the leading edges of airfols and other surfaces of aircraft. The invention relates especially to an improved infiatable shoe or container for the purpose of changingthe contour of the surface to break accumulated ice for removal of the latter in the air stream.

In some installations the wing or other airfoil is of considerable thickness at its root or inboard end and tapers in thickness rapidly toward the tip where the airfoil is comparatively thin. For most effective operation it isdesirablethat the l5 inflatable shoe be of a construction such that the Ashape-changing function of the shoeis not lessened in effectiveness by the dimensional differences of the airfoil.v

'Ihe chief objects of the invention are to provide a surface-protective shoe of improved construction, to provide a shoe of the inflatable type in Which'the construction and operation in portions thereof is suited to the dimensional characteristics of the airfoil for most effective operation, to provide improved means for securing the shoe to the airfoil, especially so that the shoe may be mounted in a condition of strong tension, to provide an improved shoe attachment by which mounting of the shoe in a curved condition about the tip of the airfoil is facilitated, and to provide durability of construction and conveni-f ence of assembly.

These and further objects will be apparent from a' description reference being had to the accompanying drawing in which:

Flg. 1 is a plan view, with parts broken away, of an airplane having protective shoes mounted at the leading edges of its wings and horizontal stabilizer, which shoes are constructed according to and embodying the invention.

Fig. 2 is a p1an`view with parts broken away of a shoebefore its application to the arfoil.

Fig. 3 is a section taken along the line 3 3 of Fig. 2.

Fig. 4 is a perspective view with parts broken away and sectioned, the view being taken at the line I--l of Fig. 1.

Fig. 5 is a section taken along the line 5--5 of Fig. 4.

Fig. 6 is a horizontal section 4of a portion of the shoe.

Fig. 7 is a view likeFig. 5, but showing a modified construction.

Fig. 8 is a view like Fig. .7 but showing a fairing element mounted on the airfoil in lieu of the protective shoe.

The invention is illustrated as applied to an inflatable shoe for preventing accumulation of ice upon the leading edges of airplane wings and 5 other airfoils. In some types of aircraft, especially in thick-winged monoplanes, the wing, and sometimes other airfoil surfaces taper in thickness very rapidly toward their tips so that if the inflatable -shoe comprises inflatable tubes of unil0 form width extending throughout the leading edge the shoe will be very effective to break up ice by changing of its surface in the thick portions of the leading edge where there is an extensive surface for ice accumulation, but the 15 shoe will be less effective in the region of the wing tip, where the tubes are not so well adapted to alter the relatively'small narrow surface presented at the leading edge. Theinvention includes the feature, among other things, of over'- 20 coming this difficulty.

Referring to Hg. 1, an airplane III comprising wings II, II and horizontal stabilizers I2, I2 has inflatable shoes I3 and I4 mounted at the leading edge of each wing, and a shoe I5 mounted 25 at the leading edge of each horizontal stabilizer. The shoes I3, Il may be spaced apart along thev Y leading edge of the wing to leave a space therebetween for a landing light or other structure in the wing.

The shoe I3, which extends over a considerable portion of the span of the wing including a thick portion thereof and a thin wing tip portion, is of the improved construction illustrated most clearly in Figs. 2 to 6. 35

The shoe preferably is elastic and adapted to be mounted in a condition of stretch upon the To this end the shoe comprises a plurality of united elastic elements, including a bottom sheet I6 and a top sheet I1 between which 40 are disposed a plurality of inatable tubes to constitute the shoe and inflatable container. The sheets and tubes preferably are of rubber to provide the desired extensibility with air`tightness.

'Ihe shoe is an elongate structure preferably 45 tapering in width in accordance with the tapering thickness of the airfoil. Throughout the greater portion of the wider end of the shoe the inflation and deflation is effected by means of a plurality of the inflatable tubes, preferably three or more, of substantially uniform crosssection throughout their lengths, these tubes being indicated at Il, I9 and 20.

In continuation of the -tubes Ilto 2l Aat the narrow end of the shoe is provided a pair ofinatable tubes 2| and 22 lying along side each other and having their adjacent walls disposed in a sinuous manner, as is shown most clearly in Fig. 2, to assure effective changing of the shape of the leading edge surface at the wing tip despite the thinness of this portion of the wing. Connections 23, 24 and 25 may be provided at the inboard ends of the tubes I8, I9 and 20 for the purpose of inflating and deflating these tubes in groups through suitable fluidcontrolling apparatus. A rubber ller strip 26a may be disposed between the tubes 2| and 22.

The tubes 2| and 22 may be infiated and deflated independently of the tubes 8 to 20, if desired, but it is preferred to provide connections so that the straight tubes and the curved tubes can be infiated and deflated in groups. As is shown most clearly in Fig. 6, the curved tubes 2| and 22 are in communication with the central straight tube I9 so that these are infiated and deflated as a group, preferably in alternation with the group consisting of straight tubes |8' and 20, the two groups being inflated and deated alternatively-as by any suitable valve mechanism, not shown, to change the surface shape for breaking up accumulated ice.

Suitable fabric tapes 26, preferably bias-laid for stretchability, may be provided at adjacent tube margins for the purpose of reinforcement. Inasmuch as the shoe is mounted under tension and is operated under tension it is desirable to provide strips 21, 21 of stretchable fabric extending across the tubes at spaced apart positions along the shoe to increase tear resistance locally so that a puncture of the rubber will not enlarge and spread undesirably along the shoe, which reinforcing feature is described and claimed in the co-pending application of Myron L. Taylor, Serial No. 160,105, led August 16, 1937.

At the upper and lower margins of the shoe, attaching means are provided for mounting the shoe upon the airfoil. As the same form of attachment may be used at both margins, only the upper one need be described. A fabric strip 28 is provided along the margin of the shoe and united to the rubber thereof, the strip being folded to accommodate a metallic strip element 29lextending throughout the margin of the shoe. Preferably the metallic strip element 29, which may be of any desired shape, but preferably is in the form of a fiat or oval wire, is loosely mounted in the fabric 28 so that the marginal material of the shoe may be slipped or gathered along the .vire 29 in the region of the tip of the wing for the purpose of permitting the shoe to be tted' around the wing tip to protect the surface. This construction permits attachment of the shoe without undesirable wrinkles, the tensioned condition of the shoe being utilized to avoid wringles in the gathered material despite the curving of the shoe margin at the wing tip.

Bevelled rubber filler strips 30, 30 may be provided at the margin of the iniiatable tubes and fabric strips 21, and the parts of the shoe structure preferably are united by vulcanization of the rubber, providing permanent adhesion.

For attaching the shoe to the airfoil, screws 3|, 3| are disposed through the shoe structure just inside thewire 29, the screws being tapped into hollow threaded rivets 32, 32 set into the metal surface or other structure of the airfoil, and the arrangement being such that the wire 29 is adapted to bear against the screws 3|, 3| to maintain the shoe in a condition of tension between its upper and lower margins. A fairing strip 33 may be provided over the margin of the shoe at the wire 29 to provide a smooth surface for the airow, and to assist in attaching the shoe, and this strip may also be held in place by the screws 3|, 3|.

In the embodiment of Fig. 7 the metal skin of the airfoil 40 is provided with a-step or offset at 4| adapted to receive the inflatable shoe so that the lattervin its deated form will provide a leading edge of the desired normal shape. A hold down strip 42 may be provided at the margin to clamp down the margin of the shoe and hold it in place by means of screws 3| 3|. When the shoe is removed, as during the summer season, a strip 43 of rubber or other suitable material (Fig. 8) may be substituted for the shoe at the offset to provide a flush surface.

Variations may be made without departing from the scope of the invention as it is defined in the following claims.

I claim:

1. Apparatus for preventing ice accumulation upon a surface comprising an elastic shoe adapted 'to be mounted upon said surface, means for securing the 'shoe' upon the surface in a condition of tension comprising a metallic strip element mounted in the shoe structure at its margin and means on the surface against which a side surface of the said strip element is adapted to bear to maintain the shoe under tension.

2. Apparatus for preventing ice accumulation upon a surface comprising an elastic shoe adapted to be mounted upon said surface, means for securing the shoe upon the surfacein a condition of tension comprising a metallic strip element mounted in the shoe structure at its margin and means on' the surface against which the said strip element is adapted to bear to maintain the shoe under tension, said metallic strip element being bendable and mounted for sliding movement in the margin of the shoe for conforming the shoe to a curved surface.

3. Apparatus for preventing accumulation of ice upon the leading edge of an airfoil comprising an elongate, elastic -shoe adapted to be mounted upon said leading edge; means for securing' the shoe upon said leading edge in a condition of tension transversely of the vshoe cornprising a metallic strip element mounted in the margin of the shoe, and means on the airfoil against which a side surface of the said strip is adapted to bear to maintain the shoe under tension;

4. Apparatus for preventing accumulation of ice upon the leading edge of an airfoil including the tip thereof, said apparatus comprising a flexible shoe adapted to be mounted upon said leading edge and about said tip, lmeans for securing the shoe to the airfoil including a metallic strip element mounted loosely-in a margin `of the shoe to facilitate adjustment of the material of the latter to curve the shoe about-said tip, and means on the airfoil for engaging said strip element.

5. An airfoil assembly comprising an airfoil, means for preventing accumulation of ice upon the leadingledge of said airfoil comprising a exible shoe mounted upon said leading edge, means for securing the shoe in such relation compris-l ing a metallic. strip element mounted in a margin of the shoe and attaching means on the airfoil extending through the flexible material Aof the shoe and abutting a side surface of said strip element for holding the shoe in place.

6. An airfoil assembly as defined in claim 5 comprising a fairing strip overlying the margin of the shoe and metallic strip element and der tachably held in place by the said attaching means.

'7. An airfoil assembly as defined in claim'5 in which the airfoil is, formed with an oiset portion providing a recess in which the margin of the shoe is disposed and secured providing a substantially flush surface in the region of said margin.

8. Apparatus for preventing accumulation of ice on aircraft comprising an elongate, elastic sheet of rubber-like material ,a plurality of distensible tubes of substantially straight walls mounted side by side along a portion of the length of said sheet, a pair of distensible tubes of varying cross-section mounted side by side along another portion of said sheet in continuation of the rst said tubes and with large portions of each opposite small portions of the other, said sheet and tubes constituting a unitary structure, means for conducting pressure fluid into and venting it from said tubes, and means for mounting said elastic sheet upon an aircraft surface with the sheet held stretched in the direction crosswise of said tubes, the mounting means comprising a metallic strip secured to the sheet along a margin thereof and a plurality of elements secured to the aircraft and positioned to be abutted by a side surface of said strip to maintain the sheet in the stretched` condition.

RUSSELL S. COILEY. 

